2006A&A...455..521K


Query : 2006A&A...455..521K

2006A&A...455..521K - Astronomy and Astrophysics, volume 455, 521-537 (2006/8-4)

Outflows from the high-mass protostars NGC 7538 IRS1/2 observed with bispectrum speckle interferometry. Signatures of flow precession.

KRAUS S., BALEGA Y., ELITZUR M., HOFMANN K.-H., PREIBISCH T., ROSEN A., SCHERTL D., WEIGELT G. and YOUNG E.T.

Abstract (from CDS):

objS{[WBN74] NGC 7538 IRS 1}{NGC 7538 IRS1} is a high-mass (30M) protostar with a CO outflow, an associated ultracompact HII region, and a linear methanol maser structure, which might trace a Keplerian-rotating circumstellar disk. The directions of the various associated axes are misaligned with each other. We investigate the near-infrared morphology of the source to clarify the relations among the various axes. K'-band bispectrum speckle interferometry was performed at two 6-meter-class telescopes - the BTA 6m telescope and the 6.5m MMT. Complementary IRAC images from the Spitzer Space Telescope Archive were used to relate the structures detected with the outflow at larger scales. High-dynamic range images show fan-shaped outflow structure in which we detect 18 stars and several blobs of diffuse emission. We interpret the misalignment of various outflow axes in the context of a disk precession model, including numerical hydrodynamic simulations of the molecular emission. The precession period is ∼280-years and its half-opening angle is ∼40°. A possible triggering mechanism is non-coplanar tidal interaction of an (undiscovered) close companion with the circumbinary protostellar disk. Our observations resolve the nearby massive protostar NGC 7538 IRS2 as a close binary with separation of 195mas. We find indications for shock interaction between the outflow activities in IRS1 and IRS2. Finally, we find prominent sites of star formation at the interface between two bubble-like structures in NGC 7538, suggestive of a triggered star formation scenario. Indications of outflow precession have been discovered to date in a number of massive protostars, all with large precession angles (∼20-45°). This might explain the difference between the outflow widths in low- and high-mass stars and add support to a common collimation mechanism.

Abstract Copyright:

Journal keyword(s): stars: formation - stars: individual: NGC 7538 IRS1 - stars: individual: NGC 7538 IRS2 - techniques: interferometric - stars: winds, outflows - hydrodynamics

Nomenclature: Table 2: [KBE2006] Source a (Nos a-r). Text: [KBE2006] Feature A (Nos A-D), <%M [KBE2006] Feature A'> (No. B').

CDS comments: (D2006.12.2)

Simbad objects: 58

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Number of rows : 58
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 IRAS 20126+4104 Y*O 20 14 25.8816769656 +41 13 36.879427236           B2.5-B0.5 440 0
2 [KBE2006] Source a * 21 13 45.330 +61 28 21.02           ~ 2 0
3 NAME SH 2-140 IRS 1 Y*O 22 19 18.277 +63 18 45.82           ~ 197 0
4 TYC 4279-21-1 * 23 12 22.0946018304 +61 26 50.241668352   11.35 10.05     K1III 2 0
5 2MASS J23130929+6128184 NIR 23 13 09.300 +61 28 18.42           ~ 1 0
6 [D75b] Em* 23-014 Em* 23 13 16.6110915192 +61 28 01.722074520           ~ 6 0
7 2MASS J23131691+6129076 Y*? 23 13 16.911 +61 29 07.61           ~ 2 0
8 [WBN74] NGC 7538 IRS 8 IR 23 13 27.3 +61 30 49           ~ 18 0
9 2MASS J23133024+6130103 Y*? 23 13 30.2430274824 +61 30 10.334305152           O9.5V+B0.5V 28 0
10 2MASS J23133184+6125161 Y*? 23 13 31.847 +61 25 16.13           ~ 2 0
11 [WBN74] NGC 7538 IRS 4 HII 23 13 32.7 +61 29 04           ~ 23 1
12 TYC 4279-1463-1 * 23 13 34.3977427416 +61 30 14.637855024   12.76 11.66     O3.5V((f*))+O9.5V 27 0
13 TYC 4279-1349-1 * 23 13 36.8131356912 +61 30 39.613105188   14.43 11.57     K 20 2
14 NGC 7538 OpC 23 13 37 +61 30.0           ~ 879 1
15 2MASS J23134351+6129372 Y*? 23 13 43.5128248824 +61 29 37.214207772           ~ 3 0
16 [WBN74] NGC 7538 IRS 3 Y*? 23 13 43.646 +61 28 14.02           ~ 65 0
17 [WBN74] NGC 7538 IRS 11 Y*O 23 13 43.901 +61 26 57.98           ~ 56 0
18 NGC 7538S Y*O 23 13 44.8 +61 26 51           ~ 90 1
19 [KBE2006] Source b * 23 13 44.810 +61 28 10.63           ~ 2 0
20 [KBE2006] Source c * 23 13 44.950 +61 28 12.33           ~ 2 0
21 [MBC98b] c Mas 23 13 45.0 +61 28 15           ~ 2 0
22 [KBE2006] Source d * 23 13 45.110 +61 28 09.69           ~ 2 0
23 [KBE2006] Source q * 23 13 45.160 +61 28 19.69           ~ 2 0
24 [KBE2006] Source m * 23 13 45.220 +61 28 12.71           ~ 1 0
25 [KBE2006] Source l * 23 13 45.240 +61 28 13.28           ~ 1 0
26 [KBE2006] Source k * 23 13 45.250 +61 28 13.05           ~ 1 0
27 [KBE2006] Source j * 23 13 45.270 +61 28 13.25           ~ 1 0
28 [KBE2006] Source i * 23 13 45.290 +61 28 13.74           ~ 1 0
29 [KBE2006] Source p * 23 13 45.290 +61 28 18.42           ~ 2 0
30 [KBE2006] Source h * 23 13 45.310 +61 28 14.72           ~ 1 0
31 [WBN74] NGC 7538 IRS 1 Y*O 23 13 45.318 +61 28 11.69           ~ 413 3
32 [KBE2006] Source r * 23 13 45.330 +61 28 08.48           ~ 1 0
33 [KBE2006] Source f * 23 13 45.340 +61 28 15.93           ~ 3 0
34 [KBE2006] Source n * 23 13 45.360 +61 28 12.99           ~ 1 0
35 [KBE2006] Source g * 23 13 45.360 +61 28 14.80           ~ 1 0
36 [KBE2006] Source e * 23 13 45.370 +61 28 15.12           ~ 3 0
37 [WBN74] NGC 7538 IRS 2 Y*? 23 13 45.4691116296 +61 28 19.985984832           ~ 74 0
38 [TGJ91] NGC 7538 NIRS 1-1W IR 23 13 45.49 +61 28 11.5           ~ 1 0
39 [KBE2006] Source o * 23 13 45.500 +61 28 10.50           ~ 1 0
40 2MASS J23134580+6124049 * 23 13 45.8098912104 +61 24 04.930569216           ~ 1 0
41 2MASS J23135808+6130484 Y*? 23 13 58.0962522720 +61 30 48.468931308           ~ 2 0
42 IRAS 23118+6110 Y*O 23 14 02.09473 +61 27 18.8460           ~ 376 0
43 [WBN74] NGC 7538 IRS 10 LP? 23 14 06.5907341040 +61 27 57.771865800           ~ 16 0
44 2MASS J23144651+6129397 * 23 14 46.5301235688 +61 29 39.595305948           ~ 1 0
45 IRAS 23151+5912 HII 23 17 21.0 +59 28 49           ~ 100 0
46 Ass Cas OB 2 As* 23 20 +60.9           ~ 67 0
47 [TGJ91] NGC 7538 NIRS 1-1N * ~ ~           ~ 2 0
48 [MBC98b] g Mas ~ ~           ~ 3 0
49 [KBE2006] Feature A * ~ ~           ~ 3 0
50 [KBE2006] Feature B' ? ~ ~           ~ 1 0
51 [AHG2004] NGC 7538 IRS B IR ~ ~           ~ 2 1
52 [MBC98b] a Mas ~ ~           ~ 2 0
53 [KBE2006] Feature B ? ~ ~           ~ 1 0
54 [MBC98b] f Mas ~ ~           ~ 2 0
55 [MBC98b] d Mas ~ ~           ~ 2 0
56 [MBC98b] e Mas ~ ~           ~ 2 0
57 [MBC98b] b Mas ~ ~           ~ 2 0
58 [MBC98b] h Mas ~ ~           ~ 3 0

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